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2 *
3 * Licensed to the Apache Software Foundation (ASF) under one
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8 * "License"); you may not use this file except in compliance
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11 * http://www.apache.org/licenses/LICENSE-2.0
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14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
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21
22
23
24 // MARKER(update_precomp.py): autogen include statement, do not remove
25 #include "precompiled_charttools.hxx"
26 #include "ExponentialRegressionCurveCalculator.hxx"
27 #include "macros.hxx"
28 #include "RegressionCalculationHelper.hxx"
29
30 #include <rtl/math.hxx>
31 #include <rtl/ustrbuf.hxx>
32
33 using namespace ::com::sun::star;
34
35 using ::rtl::OUString;
36 using ::rtl::OUStringBuffer;
37
38 namespace chart
39 {
40
ExponentialRegressionCurveCalculator()41 ExponentialRegressionCurveCalculator::ExponentialRegressionCurveCalculator() :
42 m_fLogSlope( 0.0 ),
43 m_fLogIntercept( 0.0 )
44 {
45 ::rtl::math::setNan( & m_fLogSlope );
46 ::rtl::math::setNan( & m_fLogIntercept );
47 }
48
~ExponentialRegressionCurveCalculator()49 ExponentialRegressionCurveCalculator::~ExponentialRegressionCurveCalculator()
50 {}
51
52 // ____ XRegressionCurveCalculator ____
recalculateRegression(const uno::Sequence<double> & aXValues,const uno::Sequence<double> & aYValues)53 void SAL_CALL ExponentialRegressionCurveCalculator::recalculateRegression(
54 const uno::Sequence< double >& aXValues,
55 const uno::Sequence< double >& aYValues )
56 {
57 RegressionCalculationHelper::tDoubleVectorPair aValues(
58 RegressionCalculationHelper::cleanup(
59 aXValues, aYValues,
60 RegressionCalculationHelper::isValidAndYPositive()));
61
62 const size_t nMax = aValues.first.size();
63 if( nMax == 0 )
64 {
65 ::rtl::math::setNan( & m_fLogSlope );
66 ::rtl::math::setNan( & m_fLogIntercept );
67 ::rtl::math::setNan( & m_fCorrelationCoeffitient );// actual it is coefficient of determination
68 return;
69 }
70
71 double fAverageX = 0.0, fAverageY = 0.0;
72 size_t i = 0;
73 for( i = 0; i < nMax; ++i )
74 {
75 fAverageX += aValues.first[i];
76 fAverageY += log( aValues.second[i] );
77 }
78
79 const double fN = static_cast< double >( nMax );
80 fAverageX /= fN;
81 fAverageY /= fN;
82
83 double fQx = 0.0, fQy = 0.0, fQxy = 0.0;
84 for( i = 0; i < nMax; ++i )
85 {
86 double fDeltaX = aValues.first[i] - fAverageX;
87 double fDeltaY = log( aValues.second[i] ) - fAverageY;
88
89 fQx += fDeltaX * fDeltaX;
90 fQy += fDeltaY * fDeltaY;
91 fQxy += fDeltaX * fDeltaY;
92 }
93
94 m_fLogSlope = fQxy / fQx;
95 m_fLogIntercept = fAverageY - m_fLogSlope * fAverageX;
96 m_fCorrelationCoeffitient = fQxy / sqrt( fQx * fQy );
97
98 }
99
getCurveValue(double x)100 double SAL_CALL ExponentialRegressionCurveCalculator::getCurveValue( double x )
101 {
102 double fResult;
103 ::rtl::math::setNan( & fResult );
104
105 if( ! ( ::rtl::math::isNan( m_fLogSlope ) ||
106 ::rtl::math::isNan( m_fLogIntercept )))
107 {
108 fResult = exp(m_fLogIntercept + x * m_fLogSlope);
109 }
110
111 return fResult;
112 }
113
getCurveValues(double min,double max,::sal_Int32 nPointCount,const uno::Reference<chart2::XScaling> & xScalingX,const uno::Reference<chart2::XScaling> & xScalingY,::sal_Bool bMaySkipPointsInCalculation)114 uno::Sequence< geometry::RealPoint2D > SAL_CALL ExponentialRegressionCurveCalculator::getCurveValues(
115 double min, double max, ::sal_Int32 nPointCount,
116 const uno::Reference< chart2::XScaling >& xScalingX,
117 const uno::Reference< chart2::XScaling >& xScalingY,
118 ::sal_Bool bMaySkipPointsInCalculation )
119 {
120 if( bMaySkipPointsInCalculation &&
121 isLinearScaling( xScalingX ) &&
122 isLogarithmicScaling( xScalingY ))
123 {
124 // optimize result
125 uno::Sequence< geometry::RealPoint2D > aResult( 2 );
126 aResult[0].X = min;
127 aResult[0].Y = this->getCurveValue( min );
128 aResult[1].X = max;
129 aResult[1].Y = this->getCurveValue( max );
130
131 return aResult;
132 }
133
134 return RegressionCurveCalculator::getCurveValues( min, max, nPointCount, xScalingX, xScalingY, bMaySkipPointsInCalculation );
135 }
136
137
ImplGetRepresentation(const uno::Reference<util::XNumberFormatter> & xNumFormatter,::sal_Int32 nNumberFormatKey) const138 OUString ExponentialRegressionCurveCalculator::ImplGetRepresentation(
139 const uno::Reference< util::XNumberFormatter >& xNumFormatter,
140 ::sal_Int32 nNumberFormatKey ) const
141 {
142 double fIntercept = exp(m_fLogIntercept);
143 double fSlope = exp(m_fLogSlope);
144 bool bHasSlope = !rtl::math::approxEqual( fSlope, 1.0 );
145 bool bHasIntercept = !rtl::math::approxEqual( fIntercept, 1.0 );
146
147 OUStringBuffer aBuf( C2U( "f(x) = " ));
148
149 if ( fIntercept == 0.0)
150 {
151 // underflow, a true zero is impossible
152 aBuf.append( C2U( "exp( " ));
153 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogIntercept) );
154 aBuf.append( (m_fLogSlope < 0.0) ? C2U( " - " ) : C2U( " + " ));
155 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs(m_fLogSlope)) );
156 aBuf.append( C2U( " x )" ));
157 }
158 else
159 {
160 if (bHasIntercept)
161 {
162 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fIntercept) );
163 aBuf.append( C2U( " exp( " ));
164 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogSlope) );
165 aBuf.append( C2U( " x )" ));
166 }
167 else
168 {
169 // show logarithmic output, if intercept and slope both are near one
170 // otherwise drop output of intercept, which is 1 here
171 aBuf.append( C2U( " exp( " ));
172 if (!bHasSlope)
173 {
174 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogIntercept) );
175 aBuf.append( (m_fLogSlope < 0.0) ? C2U( " - " ) : C2U( " + " ));
176 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, fabs(m_fLogSlope)) );
177 }
178 else
179 {
180 aBuf.append( getFormattedString( xNumFormatter, nNumberFormatKey, m_fLogSlope) );
181 }
182 aBuf.append( C2U( " x )" ));
183 }
184 }
185
186 return aBuf.makeStringAndClear();
187 }
188
189 } // namespace chart
190